A-0-水文水动力基本原理

FundamentalsandTheoryofHydraulicModelling

水力模型的基本原理和理论JuanGutierrez(古霆欢)&窦秋萍Whydoweneeddrainagestudies?IncreasingPopulationMajorDevelopmentsRecentFloodingEventsOngoingClimateChangeHigherExpectations2023/2/5Whatisamodel?Model?RepresentationofrealityWithaclearobjectiveFloodassessmentWaterQualityFloodforecastingsystemMasterPlanLocalfloodriskassestmentetc…05/02/2023Whatisamodel?Model?RepresentationofrealityWithaclearobjectiveFloodassessmentWaterQualityFloodforecastingsystemMasterPlanLocalfloodriskassestmentetc…05/02/2023Fitforpurpose!!!Whydoingmodelling?05/02/2023Moreadvancethantraditionalmethods(rationalmethod)AllowsyouanalysisofdifferentscenariosTraditionalmethods:Rationalmethod05/02/2023Insertfooterforallslideswith'Insert-Header&Footer'Page6CatchmentoutfallDoesnotconsiderwhathappensdownstream! ItdoesnottakeintoaccountstoragesolutionsItdoesnottakeintoaccountbackwatereffectsDisadvantages!!!Qup>>QrpVu>>VrRationalMethodQp=CIA/360Qp=peakrunoff[m3/s]C=Runoffcoefficient(between0&1)I=Rainfallintensity(constant)[mm/hr]A=Catchmentarea[Ha]360=conversionfactor7Catchmentarea=30Hectares汇水区面积=30公顷Rainfallintensity=60mm/hr降雨强度=60mm/hLanduse=mediumdensityresidentialarea（C=0.9）土地利用=中密度住宅区域（C=0.9）Q=CiA

peakflowonly!峰值流量Q=4.5m3/s8RationalMethod–Example推理法-示例

Whydoingmodelling?:

Analysisofdifferentscenarios

ModelExistingscenarioHistoricaleventsDesignevents(30,50,100,1000yrreturnperiod)FuturescenarioNewfloodingschemesbeforeconstructionNewlanduses05/02/2023TherecordsalsomostlyreferstomeasurementstakeninONEpointWhydoingmodelling?Whydoingmodelling?ModelExistingscenarioHistoricaleventsDesignevents(30,50,100,1000yrreturnperiod)FuturescenarioNewfloodingschemesbeforeconstructionNewlanduses05/02/2023ConceptsandPrinciplesofHydrology

水力学概念和原则HydrologicalCycle

水循环13Thegeneralconceptofthehydrologicalcycle

水循环的一般概念

Thehydrologicalcycleisaclosedsysteminthatwatercirculationinthesystemremainswithinthesystem.

Thewholecycleisdrivenbytheexcessofincomingsolarradiationoveroutgoingradiation.Thecycleconsistsofthesesubsystems:(i)atmospheric,(ii)surfacerunoff,(iii)sub­surface14水文循环是个封闭的循环系统，无论水以什么样形式存在，都仍然在该系统中。整个水文循环系统在太阳辐射的驱动力下进行。该循环由以下子系统组成：大气循环

地表径流(iii)地下循环ICM包括的最基本的计算引擎包括Hydrology1DRivers(nonprismatic)1DPipes(prismatic)Overlandflows2D2023/2/5Hydrological&HydraulicModels

水文水力模型Hydrologicmodel水文模型

Rainfall-runoffmodelconvertsrainfalltocatchmentrunoff降雨径流模型将降转换为汇水区径流Input:rainfallhyetograph输入：降雨过程线Output:flowhydrograph输出：流量过程线Hydraulicmodel

水力模型simulatestheflowbehaviourintheriver/pipe模拟河道/管道内的流动状态Inputs:flowhydrograph&downstreamwater-level输入：流量过程线和下游水位Outputs:water-levelsandflows输出：水位和流量16Subcatchment

汇水区Thecatchmentoutlet17汇水区排放口水文模型Hydrology1DRivers(nonprismatic)1DPipes(prismatic)Overlandflows2D2023/2/5Rainfall-RunoffModels

降雨径流模型Lossmodels(runoffvolumemodels)损失模型（径流模型）Routingmodel汇流模型19SomeRainfall-RunoffModels

一些降雨径流模型Eventbasedrainfallrunoffmodels事件降雨径流模型Formodellingonerainfallevent模拟单一降雨事件Normally24hourevent一般为24小时降雨事件Eg:designevent例如：设计降雨事件Continuousrainfallrunoffmodel持续降雨径流模型Formodellinglong-term模拟长期事件Oneseasontomanyyears一个季度甚至很多年Foryieldanalysis产水量分析20SomeRainfall-RunoffModels

一些降雨径流模型Eventbasedrainfallrunoffmodels事件降雨径流模型RationalMethod(peakflowonly)推理计算法（仅考虑峰值流量）ModifiedRational(Hydrograph)修正推理计算法（水位过程线）Time-AreaMethod时间-面积法UnitHydrographMethods单位过程线法Continuousrainfallrunoffmodel持续降雨径流模型PDM(probabilitydistributedmodel)PDM（概率分布模型）21

Hydrology

水文Page22Excessrainfall净雨量RainfallDischargePeak峰值RisingLimb涨水段Fallinglimb退水段Baseflow基流SurfaceRunoff径流Losses;损失：Toevapo-transpiration蒸发Togroundwater补充地下水Discharge(m3/s)Time(minutes)Discharge(m3/s)Time(minutes)汇水区出口的流量曲线23

Hydrology

水文RationalMethod

推理法Qp=CIA/360Qp=peakrunoff[m3/s]峰值流量C=Runoffcoefficient(between0&1)径流系数I=Rainfallintensity(constant)[mm/hr]降雨强度A=Catchmentarea[Ha]汇水区面积360=conversionfactor换算系数24Catchmentarea=30Hectares汇水区面积=30公顷Rainfallintensity=60mm/hr降雨强度=60mm/hLanduse=mediumdensityresidentialarea（C=0.9）土地利用=中密度住宅区域（C=0.9）Q=CiA

peakflowonly!峰值流量Q=4.5m3/s25RationalMethod–Example推理法-示例

Rainfall-RunoffModels

降雨径流模型Lossmodels(runoffvolumemodels)损失模型（径流模型）Routingmodel汇流模型2627SCSCurveNumber

SCS曲线数28CNSource:AGuidetoHydrologicAnalysisUsingSCSMethods,byRichardH.McCuenTime-AreaMethod

时间-面积法29降雨强度柱状图汇水区等时线图时间-面积曲线径流过程线Time-AreaMethod

时间-面积法Step(1):Delineatesubcatchmentsbasedontheisochrones基于等时线描绘子汇水区Step(2):CalculatedesignrainfallIforthewholecatchment整个汇水区的计算设计降雨Step(3):Calculateordinatesofthehydrograph计算水位曲线的纵坐标值30CalculationoftheTimeAreaMethod

时间面积法计算ABCDEFGHIJKTimeRainfallLossesERTime-AreaCurveRunoffGeneratedbytheEffectiveRainfall(inmm)Hydrograph(min)(mm)(mm)(mm)(m2)9.92.3(m3/s)00.00.00.000.000.003270001.480.001.48615.90.015.9500001.262.390.003.6599.10.09.1690001.042.031.370.004.44126.80.06.8850000.881.681.161.020.004.75152.30.02.31000000.821.420.960.870.344.41180.001.330.810.720.293.15210.000.760.610.241.61240.000.570.200.77270.000.190.19300.000.00Note:ER-EffectiveRainfall31

Hydrology

水文Page32Excessrainfall净雨量RainfallDischargePeak峰值RisingLimb涨水段Fallinglimb退水段Baseflow基流SurfaceRunoff径流Losses;损失：Toevapo-transpiration蒸发Togroundwater补充地下水UnitHydrographMethod

单位过程线法SCSUnitHydrograph33UnitHydrograph–Superposition

单位过程线-叠加Page34ExcessrainfallTime123123DischargeTimeRainfall:Statistics

降雨：统计降雨35IDF(intensity-duration-frequency)强度-持续时间-频率DDF(depth-duration-frequency)深度-持续时间-频率Rainfall:DesignStorm

降雨：设计降雨36Rainfall:DesignStorm

降雨：设计降雨37ProbabilisticDistributionModel

概率分布模型

TheProbabilityDistributedModel(PDM)isarainfall-runoffmodelbasedonprobabilitydistributedmoisturestoresandtranslationofrunoffanddrainageviaroutingstores.概率分布模型(PDM)是一种基于降雨存储分布、径流转移和排水行洪路径的降雨径流模型。38ICM中水动力模型Hydrology1DRivers(nonprismatic)1DPipes(prismatic)Overlandflows2D2023/2/5Page40FlowClassifications流态分类FlowStates流态Sub-critical缓流Slowanddeep:lowkineticenergySuper-critical湍流Fastandshallow:highkineticenergyCritical临界流

Uniquerelationbetweenvelocityanddepth,y(=A/B)Vc=(gy)1/242慢并且深：运动能量低快并且浅：运动能量低流速和深度关系唯一，y=A/BFlowStates流态Sub-critical缓流y>ycV<(gy)1/2Super-critical湍流y<ycV>(gy)1/2Criticaldepthycwhen临界流

Vc=V=(gyc)1/243Froudenumber弗劳德数Froudenumber弗劳德数

Fr=V/(gy)1/2whereVisvelocity(m/s),V—流速yisdepth(m)y—水深gisaccelerationduetogravity(m/s2)g—重力加速度Fr<1 subcriticalflow缓流Fr=1 criticalflow临界流Fr>1 supercriticalflow湍流44SpecificEnergy比能SpecificEnergyE=y+V2/2g比能方程GraphofEforafixeddischargeq固定排放系数的E曲线45Normalandcriticaldepths

一般深度和临界深度Fr<1Fr>1Fr=1Criticaldepth临界深度Subcriticalyn>yc缓流Supercriticalyn<yc

湍流46Transition-HydraulicJump

过渡——水跃47Flowprofiles流量剖面Gradually&RapidlyVariedFlow渐变流和急变流Non-UniformFlowProfiles

非均匀流剖面49WaterLevelDistanceLowTideTidallyaffectedzoneFluvialzoneHighTideTidalRiverFloodProfiles

潮汐洪水剖面50M1M2河道区潮汐影响区高潮低潮51Gradually&RapidlyVaryingFlow渐变流和急变流

Continuityequation

MomentumequationLocalaccelerationConvectiveaccelerationPressureForceGravityForceFrictionForceKinematicwaveDiffusionwaveDynamicwave52St.VenantEquations圣维南方程连续性方程

动量方程St.VenantEquations

圣维南方程Underlyingbasisfor1Dmodels一维模型的根基Assumptions:假定：Graduallyvaryingflow;渐变流；Verticalaccelerationsnegligible忽略垂直加速度Hydrostaticpressure液体静压力Mildbedslope(lessthan10deg);平缓的河床坡度（小于10度）InfoWorkscanhandlegreaterslopesInfoWorks能够处理较大坡度Fixedbed固定床1Dflow;一维流Water-surfaceishorizontal水面水平Velocitiesarearea-averaged速度为面积平均速度Manning’sEqn/CW(forsteadystateflow)isapplicable曼宁方程/CW（稳态流）适用53St.VenantEquations

圣维南方程Structures结构OftenRapidlyVaryingFlow急变流ReplaceMomentumEqnwithEnergyEqn能量方程代替动量方程Junctions交汇处Compatibilityofwater-level水位匹配Flowprofiles流量剖面Applicableforuniformflowandnon-uniformflow均匀流和非均匀流均适用ApplicableforM1(backwater),M2(drawdown),S1&S2M1（回水）、M2（跌水）、S1和S2均适用。Applicableforsteady-stateflowandnon-steady-stateflow稳态流和非稳态流均适用Applicableforsuperandsub-critical湍流和缓流均适用Criticalflow:useQ(h)临界流：用Q(h)Reproducesloopedratingcurve重新生成绳套曲线54Stage(m)Discharge(m3/s)RisingRecessionStage(m)Discharge(m3/s)RisingRecessionStage(m)Discharge(m3/s)RisingRecessionStage(m)Discharge(m3/s)RisingRecession绳套曲线衰退衰退上涨Uniformflowratingcurve(Kinematicwaveandmostlumpedroutingmodels)Loopratingcurve(Dynamicanddiffusionwavemodels)55St.VenantEquations

圣维南方程Boundaryconditions;边界条件Upstream上游Q(t)

-usual(i.e.hydrologicalmodel)H(t) -careful!Ratingcurve,Q(H) -never!!Downstream下游Q(t) -careful!H(t) -usualRatingcurve,Q(H) -usualInternalconditions内部条件Drowned,Q(Hu/s,Hd/s)Criticalflow,Q(Hu/s)56Hydraulicstructures

水工构筑物HydraulicStructures;水工建筑物OftenRapidlyVaryingFlow急变流ReplaceMomentumEqnwithEnergyEqn用能量方程代替动量方程Examples;举例Bridge桥Weir堰Gate闸门Culvert涵洞Siphon虹吸Barrage拦河坝Pump泵57St.VenantEquations

圣维南方程PartialDifferentialEquations(PDEs)偏微分方程Cannotbesolvedanalytically不能分解解Mustbesolvedbyapproximatemethods必须近似解Continuous连续的butsolvedatdiscretepointsinspaceandtime但是在时间和空间的散点上解Solvedbyapproximatemethods;用近似法解Finitedifferences:1DsolutiontechniqueinInfoWorks

—有限差：InfoWorks的一维解法581Dvs2D592DHydaulics1Dengineforpipednetworksandrivernetworks管网和河道的一维引擎2Dengineforfloodplainandabove-groundsystems(overlandflow)&non-1Dflowaroundstructures漫滩区、地面以上系统和构筑物内的非一维流2DFlowEquations

二维流量方程Basedontheshallowwaterequations,iethedepth-averagedversiontheNavier–StokesEqns浅水方程，即纳维斯-斯托克斯方程602DFlowSolverInfoWorks2Dcomponent;InfoWorks的2D组件Solvesconservationofmass&momentum质量守恒和动量守恒Finite-volume,Explicitsolver,Unstructuredmesh有限体积，非结构网格thesolverisfullyconservativeandshock-capturing,soparticularlysuitableforthesimulationofrapidlyvariedflows.解法非常保守，适合急变流的模拟61Prismaticandnotprismaticlinks

柱状连接和非柱状连接05/02/2023Prismatic柱状NonPrismatic非柱状Prismaticandnotprismaticlinks

柱状连接和非柱状连接05/02/20233Dview3D视图Prismatic柱状Planview平面视图NonPrismatic非柱状River1D-2Dconnection

河道1D-2D连接05/02/2023Advantagesofunstructuredmesh

非结构网格的特点Page65Page66Test4:Circulardam-breakwave-initiallydrybed

溃坝洪水波-干涸河床Page67InfoWorks2DNote:Distancebetweenconcentricallygreycircles=500mPage68Aregularmeshsoftware

常规网格软件Depth(m)Note:Distancebetweenconcentricallygreycircles=500m,Dryweatherflows

Flowsurvey(3or4days)Pumpingstation/WWTWdataDiurnalcycles,etc.StormeventsFlowsurvey(3events)Pumpingstation/WWTWdataTide/riverlevelsModelVerificationIssuestoconsiderAssessmentofflowsurveydataAllocationoffoulflows:locationsflowratesdiurnalflowprofilesInfiltration/baseflows/tidalinflowAllocationofimpermeableareasSoil/runoffparametersInfiltrationmoduleModellingofancillariesItemstocompare:FlowratesVelocitiesDepthsVolumesHistoricverificationRainfalldataFloodingrecordsPumpingstation/WWTWdataCSOspillsTide/riverlevelsModelVerificationReviewReporting:ModelBuild/VerificationReportTobebasedonGDSDSreporting(Phase2)CommentsonsourcesofdataAssetsurveyImpermeableareasurveyCCTVsurveyFlowsurvey–includingmonitorperformanceModelbuildprocessUseofavailabledataAncillaries–pumpingstations,CSOs,etc.ModelverificationprocessVerificationresultsGraphicalcomparisonsTabulardataDiscussion–keyissues/modelsuitabilityHydraulicAssessmentDesignStorm–existingmodelFlood&surchargefrequenciesSyntheticDesignStormsLocalrainfallparametersRangeofdurationsReturnperiodsDesignStorm–futuremodelUpdatingofmodelforfutureFlood&surchargefrequenciesTimeSeries–existingmodelCSOspillfrequencies&volumesFutureModelUpdatesFuturedevelopments&populationsProposeddrainageimprovementsChangestopopulation,waterusage,tradeflows,etc.Climatechange(seeGDSDSpolicy)HistoricalRainfallSeriesChoiceofsuitablerainfalldata-synthesisedifnecessary(e.g.TSRSim)TimeSeries–futuremodelUpdatingofmodelforfutureCSOspillfrequenciesHydraulicAssessmentReviewHydraulicAssessmentStagesReporting:HydraulicAssessmentReportDigitalplans–usingMapInfoTobebasedonGDSDSreporting(Phase2/Phase3)ExistingandfutureperformancesFlooding&surcharging(X-Xdiagrams)CSOperformanceSpillfrequenciesSpillvolumesPFFsatspillsFormulaAflowsPlanofExistingPerformanceProposedImprovementOptionsCloseliaisonbetweenTobin&HRWteamsImprovementslikelytoinclude:Localrepairs/rehabilitation(sewers&manholes)UpsizingofsewersNewsewersSurfacewaterseparationStorageprovisionCSOimprovementsBasedonvariousperformancedeficiencies